For the first time researchers have been able to gather enough biomass in the form of DNA to apply molecular methods to samples from two large dust plumes originating in Asia in the spring of 2011. The scientists detected more than 2,100 unique species compared to only 18 found in the very same plumes using traditional methods of culturing, results they published in July.
"The long-range transport and surprising level of species richness in the upper atmosphere overturns traditional paradigms in aerobiology," says David J. Smith, who recently earned his doctorate at the University of Washington in biology and astrobiology. He’s lead author of a paper in the current issue of the journal Applied and Environmental Microbiology.
"It’s a small world. Global wind circulation can move Earth’s smallest types of life to just about anywhere," Smith said.
It’s been estimated that about 7.1 million tons (64 teragrams) of aerosols – dust, pollutants and other atmospheric particles, including microorganisms – cross the Pacific each year. The aerosols are carried by wind storms into the upper reaches of the troposphere. The troposphere, the layer of air closest to earth up to about 11 miles (18 kilometers), is where almost all our weather occurs.
Co-author Daniel Jaffe, professor at UW Bothell, has previously documented especially large plumes of aerosols in the troposphere making the trans-Pacific trip in seven to 10 days. The recent findings are based on two such plumes, one in April and the other in May of 2011, detected at Mount Bachelor in the Cascade Mountains of central Oregon.
Most of the microorganisms – about half were bacterial and the other half fungal – originated from soils and were either dead on arrival or harmless to humans. A few fungal species have been associated previously with crop wilt but scientists had no way of determining if any crops were affected during either plume event.
Most of the species in the plumes can be found in low, background levels on the West Coast. The plumes, however, brought elevated levels of such organisms leading the scientists to say that it may be useful to think about microorganisms as air pollution: microorganisms that are unnoticed in background levels might be more relevant in concentrated doses.
"I was very surprised at the concentrations. One might expect the concentrations of cells to decrease with altitude based on fallout and dilution," Smith said. "But during these plume events, the atmosphere was pooling these cells just as it does with other kinds of air pollution."
Interestingly, Smith says, two of the three most common families of bacteria in the plumes are known for their ability to form spores in ways that they can hibernate safely during harsh conditions, making them especially well adapted to high altitude transport.
"I think we’re getting close to calling the atmosphere an ecosystem," Smith said. "Until recently, most people would refer to it as a conveyor belt, or a transient place where life moves through. But the discovery of so many cells potentially able to adapt to traveling long distances at high altitudes challenges the old classification."
Cells also can interact with their high-altitude environment, for example, becoming the nucleus for rain drops and snow flakes and influencing the amount of precipitation that falls. Other scientists estimate that 30 percent of global precipitation stems from microbes.
On the other hand, scientists have yet to see evidence of metabolism or growth of microorganisms while aloft and there’s a limited amount of time that any organism might reside there.
Sampling the upper troposphere for microorganisms in the past has been a spotty effort using aircraft and balloons, Smith said.
"Because it is so difficult to get samples, I argue it’s probably the last biological environment on the planet to be explored," he said.
Mount Bachelor, like many other mountains in the Cascades, has a peak tall enough to pierce the upper troposphere. Unlike other mountains in the Cascades, however, the top of Mount Bachelor is a far more accessible place for an observatory because a ski area exists there. There’s power and bringing equipment and personnel to the observatory is not a major undertaking, you just take the ski lift.
Funding for the work came from the National Science Foundation, National Geographic Society, NASA's Astrobiology Institute, the UW's NASA Space Grant Consortium and the UW Department of Biology.
Other co-authors are Peter Ward and Hilkka Timonen with the UW and UW Bothell respectively, Dale Griffin with the U.S. Geological Survey, Michele Birmele and Michael Roberts with NASA and Kevin Perry with the University of Utah.For more information:
Sandra Hines | Newswise
Litter is present throughout the world’s oceans: 1,220 species affected
27.03.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy